Clearer – A Gesture-Driven Windows 8 To-Do Application

using System;
using System.Collections.Generic;
using System.Linq;
using Windows.UI.Xaml;

namespace ClearStyle.Interactions
{
  /// <summary>
  /// Manages a collection of interactions, multicasting various functions to each interaction (such
  /// as the need to attached to a new element), and also manages the enabled state of each interaction.
  /// </summary>
  public class InteractionManager
  {
    private List<IInteraction> _interactions = new List<IInteraction>();
    
    public void AddInteraction(IInteraction interaction)
    {
      _interactions.Add(interaction);
      interaction.Activated += Interaction_Activated;
      interaction.DeActivated += Interaction_DeActivated;
    }

    /// <summary>
    /// 'multicast' AddELement to all interactions
    /// </summary>
    public void AddElement(FrameworkElement element, FrameworkElement transformElement)
    {
      foreach (var interaction in _interactions)
      {
        interaction.AddElement(element, transformElement);
      }
    }

    private void Interaction_DeActivated(object sender, EventArgs e)
    {
      // when an interactions is de-activated, re-enable all interactions
 	    foreach(var interaction in _interactions)
      {
        interaction.IsEnabled = true;
      }
    }

    private void Interaction_Activated(object sender, EventArgs e)
    {
      // when an interaction is activated, disable all others
 	    foreach(var interaction in _interactions.Where(i => i != sender))
      {
        interaction.IsEnabled = false;
      }
    }
  }
}